(Revised Abstract) DESCRIPTION: This Core will provide equipment, services and expertise in biotechnology and combinatorial chemistry to facilitate development of novel peptide imaging agents for the Center. Much of the methodology is established. It brings together a Biotechnology Core that has been put in place during the P20 phase with a recently established peptide synthesis resource, under a single leadership. An extensive list of services to be provided is detailed in the application, both in the biotechnology component and in the peptide synthesis. There is strong linkage to the Radiolabeling and Bioconjugate Core, with a plan to share postdoctoral fellows and undergraduate trainees from the Career Development Program (CDP). The examples of agents that have been developed attest to the high level of sophistication and capabilities of the Core. Detailed alternate strategies are presented for peptide synthesis. The utilization of the Core by the other projects is well documented: it will be used by all five Research Projects, at utilization rates ranging from 5 to 25 percent and by all four Development Projects at a combined utilization of 25 percent. Thus, the Core is fully utilized and essential across the Center's program.